Former South Korean President Park Geun-hye, left, arrives for her trial at the Seoul Central District Court in Seoul. Picture: AP Photo/Ahn Young-joon

Seoul - Supporters of former South Korean president Park Geun-hye have asked a United Nations body to investigate whether her detention during her corruption trial was preventing Park from getting proper medical treatment, a barrister said on Tuesday.

Park, ousted earlier this year and in detention since March, is undergoing a lower court trial for charges of abuse of power and bribery. Her current detention period for the lower court trial is due to end on October 17, which the prosecution asked the court to extend on Tuesday.

A legal team working for Park's supporters has asked the U.N. Working Group on Arbitrary Detention in Geneva to look into whether Park was given medical treatment and whether there were procedural irregularities in her current trial, said Rodney Dixon QC, a London-based human rights barrister.

"She is not a flight risk... She has been denied opportunity to receive adequate medical care through provisional release or options of house arrest," said Dixon.

Since her detention began in late March, Park has declined witness appearances in concurrent trials citing health issues, and various South Korean media have reported her as having chronic back and shoulder pains, difficulty sleeping and nodding off more than once during hearings.

South Korea's justice ministry, which oversees the Seoul Detention Centre where Park is held, said all detainees are guaranteed ample chances to receive medical care both inside the centre and at outside medical facilities when needed, and as such Park is receiving proper medical care.

The ministry declined to disclose Park's exact medical conditions as they are private.

Seoul Central District Court, where Park's trial is ongoing, directed questions about Park to the justice ministry as detention is its purview.

The U.N. Working Group on Arbitrary Detention did not respond to a request for comment.

Although the U.N. Working Group on Arbitrary Detention does not have the power to enforce an action, it can seek information from the South Korean government, organise a visit to Park to investigate and announce its findings.

The team working on behalf of Park's supporters said in a statement this month it will also bring Park's case before the U.N. Human Rights Council in November during a periodic review of South Korea's human rights compliance.